Surgical retractors are used for holding tissue, at the edge of a surgical incision or wound, away from the field of the operation. One particular type of retractor employs a support mechanism to which the actual retractor elements can be attached. This type of retractor is commonly used in abdominal surgery and also in brain surgery. In abdominal surgery the retractor is positioned over the abdomen of the patient. Moveable retractor arms are positioned to hold body tissue surrounding the incision away from the field of the operation. In brain surgery, the retractor is similarly used to keep tissue away from the field of the surgical procedure.
A particular type of retractor used in both abdominal and brain surgery is a retractor which has a frame to which individual arms, having retractor blades at their ends, can be attached. The positioning of the retractor on the frame can be adjusted so that the retractor can be used to adjust the retractor blades in the proper position for different types of surgery.
Examples of such retractors are those disclosed in U.S. Pat. Nos. 1,839,726; 2,594,086; 3,522,799; 4,099,521; 4,254,763 and 4,457,300. All of these retractors include a frame to which different types of retractor elements can be attached. The retractor blades themselves can be adjusted to position the retractor blades in a proper location to keep tissue away from the operative field during the surgical procedure. The retractor disclosed in U.S. Pat. No. 4,099,521 is a ring shape retractor in which a portion of the ring is removable.
The retractor disclosed in U.S. Pat. No. 4,457,300 is ring shaped and has a dovetail slot around the outer circumference of the ring. The disclosure of U.S. Pat. No. 4,457,300 is incorporated herein by reference. Retractor elements can be fitted into the dovetail slot and secured in various positions. An improvement to the ring shown in U.S. Pat. No. 4,457,300 provides a two component ring which has a portion which can swivel 180.degree. to provide greater access to the operative site if desired. The swivel portion of the ring is attached to the fixed portion with a pair of pivot mechanisms which fit into the dovetail slot around the outer circumference of the ring. There is a sunburst clamp on one side of the ring which may be disengaged to allow the swivel portion of the ring to rotate. The swivel portion of the ring also can be removed from the fixed portion of the ring by the removal of the pivot mechanisms from the dovetail slot on opposite sides of the fixed portion of the ring.